Riveter



J. C. HANNA May 9, 1933.

RIVETER Filed April 11,-1929 f wmm 7..' jL. JH www M* a all Emil Patented May 9, 1933 UNITED STATES PATENT oFFicE JOHN O. HAN'NA, OF CHICAGO, ILLINOIS, 'ASSIGNOB T0 ENGINEERING WORKS,

` F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS Application med'aprn 11, 1929. serial no. 354,876.

.This inventionrelates to improvements in riveting. machines or machines of like character in which fluid pressure is employed to obtain the necessary force for performing u crushing, punching, embossing or similar effects, and in which the' force is transmitted either directly from a piston tothe die or vthrough the intervention of toggles, levers or other means for multiplying the intensity ,10 of the initial force.I

According to the customary practice an approximate uniform standard of Huid pressure is maintained for connection to riveters or presses, and, inasmuch as the .force re- 15 guired for particular operations will vary 1n accordance with the dimensions of the material being fabricated, it would, thereflore, be necessary to have a plurality of machines, each of which is so proportioned as to develop the desired pressure of the particular operation. Such an outlay of equipment would be necessarily expensive. It is, therefore, desired that some means be developed which may be readily adaptable to 95 standard riveters and which will serve-to limit the maximum pressure developed to a predetermined amount. It is, of course, desirable that the means be adjustable so thepredetermined force may be varied. 30 It is a purpose of this invention to provide improved means which will efficiently limit the maximum pressure developed in a riveting or like machine and which will positively and eiiciently operateby acting directly on a controlling member for the main valve of the riveter.

It is a further purpose of the present invention to so design the mechanism that upon the reaching of the maximum desired pressure in the riveter, the pressure is automatically cut ofi and the parts returned to the normal position.

Another purpose of my invention consists in the provisionof an apparatus which will operate as above described independently of the control of an operator. That is, in a riveter in which there is a manual control lever, even though the operator holds -the 5o lever in worlng position, the pressure be cut off and the dies separated when the desired maximum pressure is reached.

In articular, the present improvements inclu e a piston which is connected directly to the main D valve of the machine and which is` resistedv in its movement by adjustable spring means which are so connected that there is a minimum of friction between the movable parts, and, further, the resisting means is so designed that once the movement of the piston to move the D valve to return position has started, the resistance will decrease and the movement will be quickly and fully completed.

Other objects and advantages of my improvements will be more readily apparent as the description proceeds in connect1on with the attachedV drawing in which a preferred| Y 'embodiment of the improved mechanism is with a standard e piston.

The invention as illustrated is mountedl upon a neumaticriveter of the compression toggle joint type but it will be readily apparent that the improvements are adaptable to any of the ordina-ry riveters or similar machines in which there is a fluidcylindei .which receives pressure from a source havin anniform maximum pressure. There is s own 'a v main cylinder 1 in which slides the main piston head 2 which is connected through simple levers and toggles toa vertically slidable ram 3 carrying an upper die 4 which cooperates with a fixed lower die 5 mounted in the other arm of a U-shaped riveting frame 6.

A. pressure line 7 is` shown extending to the working end'of the cylinder, while a the cylinder 1. Fluid pressure is supplied through the inlet pipe 9. The pipe lines 7, 8 and 9 are suitably connected to a valve chest and housing 104in which is mounted the D Valve 11 of the ordinary type for controlling port 12 to the working end of the main cylinder 1, port 13 to the return end of the main cylinder-1 and exhaust port 14. In the position shown, the D valve 11 is in position to admit fluid pressure from the pipe line 9 to the port 12 and to the head end of the cylinder 1 which will cause the movement of the piston 2 and the operation of the upper die 4.

' A valve operating r'od 15`is shown connected to the Dvalve by-the nuts 16 at both sides of the valve and extending through opposite ends ofthe valve chest 10. To the upper end of the valve rod 15 is secured an enlarged extension 17 which is designed to be releasably connected to a' grip block 18.

The lever 19 is the usual control lever which extends adjacent they operating -end of the machine whereby the operator may readily grasp the lever in order to initiate the riveting operation.. The lever 19 is fulcrumed on shaft 20 and is formed at its endwith a yoke 21 having-slots 22 in the arms which engage transversely extending pins 23 from the grip block 18.

In the usual construction the lever 19 is directly connected to the rod holding the D valve, but in-my construction the gri-p block 18 is releasably connected to the extension 17 ofthe valve rod 1 5v for a purpose whichwill be later apparent. 'I he enlarged extension 17 is therefore/ provided with a circular .groove 24and a'ball 25 is pressed `in engagement with' thev groove. .24 by plunger 26 which is mounted to slide in the wall of theV grip block 18. Plunger 26 is pressed to Aengage the ball 25 by spring 27 the resistance of which may be adjusted by the springl cap ATo the lowerend of the valve rod 15 is secured a piston 29 which slides'in a cylinder -30. The vcylinder 30 in the present construction is 'attached directly to thelowerend of the valve chest 10 and suitablepackng is providedtoprevent the escape of the pressure through'the bearings for the slidable valve' rod 15. To one end ofthe cylinder 30 is coni nected a pipe line 3lwhich is also connected `to the housinglO in communication with the' port 12 to the head end of the main cylinder 1. The pressure upon the piston 29 tendingY to move the' D valve downwardfromthe position shown' will therefore be'the same as the pressurefupon' the mai-n piston 2,'and .suitable means 'is provided to resist .the movement of the piston. 29 together with the D-valve`11 until adesredmaximum pressure has been attained.

\ In the design shown, the lower end-of the valve rodl which extends through thepis- 32 which engage rollers 33. The rollers 33 are held in engagement with the oblique wedge surfaces 32 by the arms 34 which are Y pivoted at 35 to the lower end of the cylinder 30. The levers 34 are normally moved towards each other by the springs 36 which are designed to exert their force against V- shaped we dges 37 which engage knife edge bearings 38 formed in lthe lower ends of the levers 34. The springs 36 surround rods 39 .which are attached to the V-shaped wedges through the rollers 33 to the obliquey surfaces 32 of the valve rod 15, and therefore, produce vertical components of pressure which will tend to resist the movement of the piston 29 until the pressure on the piston 29 overcomes the pressure developed by the springs 36.

When sufficient pressure has been developed on the piston 29, the'valve rod 15 will be moved downward thus shifting the D-valve 11 and causing the 'admission of Huid pressure to the return end of the main cylinder 1 which eifectuates a return of the piston 2 and an upward movement ofthe die 4. The final position of the lower end of the valverod 15; is illustrated in Figure 4 from-which it is apvparent that the rollers 33 now act against the plane vertical sides of the valve rod 15 and therefore do not develop any vertical component of pressure. .Thus it will be evident that when the piston 29 starts to move downward, the resistancedeveloped by the springs 36 will produce diminishing vertical components of pressureand cause the piston 29 to quickly complete a full movement. It'will be A' further noted that the inner faces of the pivoted levers 34 are initially disposed angular vto the axisofmovement of the rod 15 and .action of the wedge surfaces in forcing the rollers apart, the levers 34 are moved about the1r pivots 35 towards positions substantial.- ly paralleltov the axis of movement of the vrod 15.` The diminishing relative angle between each of thelev rs and theaxis of movement of the rod 15 teilids to decrease the effective resistance produced by the springs 36 even before the rollers have reached -the straight sides of the rod 15.

As statedbefore, the operating lever 19 is e releasably connected. tothe valve rod 15 whereby,even 'the operator is holding the liao lever in the working position shown in Figure 1, the D valve will be moved downward and relative movement between the extension member 17 and the grip block 18 Will occur due to the spring pressed ball being forced out of the groove 24 into bearing engagement with the cylindrical surface 'of the extension 17 For the next operation the operator only needs to. raise the lever 19 to reengage the grip block 18 and then, upon a downward movement of the lever 19, the D valve together with the valve rod 15, will be again moved to the position shown in Figure 1. The downward movement of lever 15 is limited by 'a stop member 42 shown in Figure 1.

The advantages `of such design will be clearly apparent. The operator may adjust the resistance of the springs in order to vary the resisting component of pressure upon the valve rod 15 in accordance with the particular materials which are beingoperated upon. By directly connecting the piston 29 to the means for moving the D-valve, there isl no opportunity for leakage of the iuid pressure and the parts will more delicatelyrespond to the pressure developed in the head end of the cylinder.

It is to be understood that various changes and modilications'may be made in the particular embodiment of my invention without deexpressed in the appended claim.`

I claim:

parting from the spirit of the invention as I n combination with a machine for performing a riveting or like operation, a main cylinder, a main piston foroperating a working member, fluid connections to the endy of said main cylinder, ama-in valve for controlling said iuid connections, an ,auxiliary cylinder, an auxiliary piston in said auxiliary'.4

cylinder, a fluid connection to one end of said auxiliary cylinder adapted to receive the pressure developed in the working end of the main cylinder, means for moving said main valve by the movement of said auxiliary piston, means for resisting the movement of said auxiliary piston which will not yield and allow movement until'the development of a predetermined working pressure in said mainlcylinder, said last-namedA means including a wedge shaped extension from. said auxiliary i piston, roller's'adapted to be pressed into engagement with the wedge surfaces of said extension and adjustable springs for developl ing pressure upon said rollers.

signed at chicago, nunoiawhjs 5th a@ of April, 1929.

JOHN C; 'HANNA 

